This invention relates to a novel high frequency magnetic field coupling arc plasma reactor.
If, in the case where a chemical reaction is allowed to take place by using an arc plasma, a reactive material is introduced into the torch, then the reactant or product is necessarily reacted with or stuck to the inner wall of the torch, with the result that the torch is corroded, impurities are mixed, and the plasma becomes unstable. If the reaction causes great heat absorption, it is disadvantageous in energy effect. Accordingly, in general, it is not preferable to introduce a reactive material into the torch. Therefore, a method in which the reactive material is introduced around the plasma jet is extensively employed in the art.
However, since the arc plasma jet is essentially a magnetic fluid whose specific feature resides in its high heat pinch or magnetic pinch effect, the reaction material cannot readily mix into the plasma jet. That is, the reaction material enters only the peripheral portion of the plasma jet where the energy density is low, and the reaction of the reaction material occurs only in the tail flame of the plasma jet. Accordingly, it is difficult to effectively utilize the energy of the arc plasma.
A number of methods of introducing a reaction material into a plasma jet have been proposed in the art. However, at the present, it is difficult to say that these methods successfully introduce the reaction material directly into the plasma jet for satisfactory reaction.
On the other hand, in the case of a high frequency plasma, its heat pinch and magnetic pinch effects are not so high, and therefore its plasma flame is large in volume and relatively low in velocity. Therefore, if it is possible to carry out the reaction in this plasma flame, then a variety of merits may be obtained because the reaction space of the reaction material is increased and the staying period of time of the same is also increased. However, this still involves problems to be solved. A first one of the problems is that even if the reaction material is forced to be introduced into the high frequency plasma flame, it merely passes along the peripheral portion of the plasma flame and cannot pass through the central portion thereof because of a back-flow phenomenon attributed to magnetic pressure as is well known in the art. A second problem is that the plasma flame is liable to become unstable by the introduction of the reaction material into the plasma flame.